Parkinson's Disease Lecture Notes

Overview

• Parkinson's Disease is a neurodegenerative disorder.
• Affects about 0.3% of the population over age 40, totaling approximately 7.5 million people worldwide.

Signs and Symptoms

• Cardinal Features:
  • Tremors
  • Rigidity
  • Bradykinesia
  • Postural instability
• Cranial Facial Symptoms:
  • Hypomimia (decreased facial expression)
  • Dysphasia (difficulty swallowing)
  • Hypophonia (reduced voice volume)
  • Visual problems (blurred vision, eyelid issues)
• Gait Disturbances:
  • Shuffling
  • Festination
  • Freezing

Brain Anatomy Related to Parkinson's

• Basil Ganglia: Critical for muscle tone and movement coordination.
• Thalamus: Connects cortex to brain stem and spinal cord.
• Key Structures in Basil Ganglia:
  • Caudate Nucleus
  • Putamen
  • Globus Pallidus (external and internal)
  • Subthalamic Nucleus
  • Substantia Nigra

Function of Basil Ganglia

• Initiates and smooths out voluntary movement.
• Signal Pathway:
  1. Cortex sends signals to Basil Ganglia.
  2. Basil Ganglia processes and sends signals back to Motor Cortex.
  3. Motor Cortex sends signals to muscles for movement.
• In Parkinson's, disruption occurs in signal transmission, affecting movement.

Pathophysiology

• Normal Function: Dopamine from Substantia Nigra facilitates smooth and controlled movements.
• Parkinson’s Disease:
  • Reduced dopamine due to neuron death in Substantia Nigra.
  • Neuron death may result from:
    • Protein misfolding and aggregation
    • Defective proteolysis
    • Mitochondrial dysfunction
    • Oxidative stress
• Effect: Lack of dopamine disrupts normal inhibitory and excitatory pathways, leading to movement issues.

Pathology

• Affected Area: Substantia Nigra
• Changes Observed:
  • Demyelination
  • Neuronal loss
  • Gliosis
• Hallmarks:
  • Lewy bodies (eosinophilic intracytoplasmic inclusions containing alpha-synuclein)

Risk and Protective Factors

• Risk Factors:
  • Genetic: GBA, SNCA, LRRK2, Parkin, Pink1
  • Environmental: Pesticides
• Protective Factors:
  • Smoking
  • Coffee consumption
  • Vigorous exercise
  • Use of non-steroidal anti-inflammatory drugs

Conclusion

• Discussed the signs, symptoms, neuroanatomy, function of basil ganglia, pathophysiology, pathology, and risk factors related to Parkinson's Disease.